Electronic devices (cellular telephones, wireless modems, computers, digital music players, Global Positioning System units, Personal Digital Assistants, gaming devices, etc.) have become a part of everyday life. Small computing devices are now placed in everything from automobiles to housing locks. The complexity of electronic devices has increased dramatically in the last few years. For example, many electronic devices have one or more processors that help control the device, as well as a number of digital circuits to support the processor and other parts of the device.
Amplifiers are commonly used in various electronics devices to provide signal amplification. Different types of amplifiers are available for different uses. For example, a wireless communication device such as a cellular phone may include a transmitter and a receiver for bi-directional communication. The receiver may utilize a low noise amplifier (LNA), the transmitter may utilize a power amplifier (PA) and the receiver and transmitter may both utilize variable gain amplifiers (VGAs).
Amplifiers may be fabricated with various integrated circuit (IC) processes. Sub-micron complementary metal oxide semiconductor (CMOS) fabrication processes are commonly used for radio frequency (RF) circuits in wireless devices and other electronic devices in order to reduce cost and improve integration. However, transistors fabricated with sub-micron CMOS processes typically have small physical dimensions and are more susceptible to stress and possibly failure due to electrostatic discharge (ESD). ESD is a sudden large and momentary electrical charge that may come from static electricity and/or other sources. It is desirable to effectively combat ESD while minimally affecting performance.